QueryWrapper查詢

package cn.bitqian;

import cn.bitqian.entity.User;
import cn.bitqian.mapper.UserMapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

/**
 * @author echo lovely
 * @date 2020/11/17 08:19
 */

@SpringBootTest
public class WrapperDemo {
    
    


    @Autowired
    private UserMapper userMapper;

    // 測試普通的條件查詢
    @Test
    void test1() {
    
    

        // 條件構造器
        QueryWrapper queryWrapper = new QueryWrapper<>();
        // 查詢name為jack的人 並且年齡大於等於3歲
        queryWrapper.eq(true,"name", "Jack").
                ge("age", 3).
                between("age", 10, 20);

        User user = userMapper.selectOne(queryWrapper);
        System.out.println(user);

        queryWrapper.clear();


    }


    // 測試模糊查詢 demo
    @Test
    void test2() {
    
    
        // 查詢構造器
        QueryWrapper userWrapper = new QueryWrapper<>();

        // condition 條件為 false 不包含該條件查詢
        // LIKE '值%'
        userWrapper.like("name", "J").likeRight(false, "name", "e");

        List users = userMapper.selectList(userWrapper);
        users.forEach(System.out::println);
    }

    // 測試子查詢
    @Test
    void test3() {
    
    
        // ==>  Preparing: SELECT id,name,age,email,version,
        // deleted,gmt_create,gmt_modify FROM user WHERE deleted=0
        // AND (id IN (select id from user where id < 3))
        QueryWrapper userWrapper = new QueryWrapper<>();
        userWrapper.inSql("id", "select id from user where id < 3");

        List users = userMapper.selectObjs(userWrapper);
        users.forEach(System.out::println);
    }

    // order by ..
    @Test
    void test4() {
    
    

        QueryWrapper userWrapper = new QueryWrapper<>();

        userWrapper.orderByDesc("id");

        List users = userMapper.selectList(userWrapper);

        users.forEach(System.out::println);
    }



}

查詢方式

說明

setSqlSelect

設置 SELECT 查詢字段

where

WHERE 語句，拼接 +?WHERE 條件

and

AND 語句，拼接 +?AND 字段=值

andNew

AND 語句，拼接 +?AND (字段=值)

or

OR 語句，拼接 +?OR 字段=值

orNew

OR 語句，拼接 +?OR (字段=值)

eq

等於=

allEq

基於 map 內容等於=

ne

不等於<>

gt

大於>

ge

大於等於>=

lt

小於<

le

小於等於<=

like

模糊查詢 LIKE

notLike

模糊查詢 NOT LIKE

in

IN 查詢

notIn

NOT IN 查詢

isNull

NULL 值查詢

isNotNull

IS NOT NULL

groupBy

分組 GROUP BY

having

HAVING 關鍵詞

orderBy

排序 ORDER BY

orderAsc

ASC 排序 ORDER BY

orderDesc

DESC 排序 ORDER BY

exists

EXISTS 條件語句

notExists

NOT EXISTS 條件語句

between

BETWEEN 條件語句

notBetween

NOT BETWEEN 條件語句

addFilter

自由拼接 SQL

last

拼接在最后，例如：last(“LIMIT 1”)

 

    public User getByIdNumber(Long idNumber) {
        QueryWrapper<User> queryWrapper = new QueryWrapper();
        queryWrapper.lambda()
                .eq(User::getIdNumber, idNumber)
                .gt(User::getIdAuthStatus, 0);
        return userMapper.selectOne(queryWrapper);
    }
and ( pid = 0 or pid is null)  用法

        QueryWrapper<Resource> queryWrapper = new QueryWrapper();
        queryWrapper.and(wrapper -> wrapper.eq("pid", "0").or().isNull("pid"));
        queryWrapper.orderByAsc("sort");
        List<Resource> list = resourceMapper.selectList(queryWrapper);
 
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版權聲明：本文為CSDN博主「秋名山車神不開車」的原創文章，遵循CC 4.0 BY-SA版權協議，轉載請附上原文出處鏈接及本聲明。
原文鏈接：https://blog.csdn.net/weixin_34503526/article/details/111725076